Preheat your oven to 350°F (180°C). Grab a pan and place on medium-high heat. Add oil and then butter into the hot pan until the butter has melted
Next, add your chopped onions, garlic paste, and mushrooms and cook on medium-high heat until veggies are soft and translucent for about 5 minutes. Once veggies are done cooking set aside.
Take half (1 cup) of your pre-cooked lentils and blend together in your food processor. This will help your loaf bind together. Add your processed lentils to a large mixing bowl along with the other unprocessed whole lentils.
In your large mixing bowl also add cooked mushrooms and onions, thawed out vegan beef crumbles, ketchup, Vegan Worcestershire Sauce, vegetable bouillon, fresh parsley (or dried Italian herbs), sea salt, black pepper, bread crumbs, and instant oats.
Mix together until fully combined, gently smashing together (not too much tho). You can get messing and use your hands for this. It's kinda fun!
Line your pan with parchment paper for an easier cleanup or lightly grease your baking sheet or loaf pan with oil. Add your mixture to your baking sheet forming it into a loaf (it should hold with no problem). Or add it to your loaf pan and pat down.
Top with vegan BBQ sauce or your own personal favorite meatloaf sauce. Put in oven and bake for 15-20 minutes. Take out and let cool. The longer it cools the more it holds when you cut it. Top with additional vegan BBQ sauce and serve with your favorite sides!